Abstract/Summary Attention-Deficit/Hyperactivity Disorder (ADHD) affects 11% of children and leads to adverse outcomes[1,2]. These include impaired psychosocial, educational, and neuropsychological development, lower achievement levels across domains, and distress, often continuing into adulthood[3?7]. Medications, while often effective in reducing certain ADHD symptoms, have many disadvantages, including misuse and side effects[8?15]. Behavioral interventions do not have these adverse effects, but they are not as effective[9,10]. Mindfulness has been the subject of increasing academic and clinical attention[16]. In recent years, it has been studied in adult populations for a variety of medical and psychiatric conditions, and it is known to be effective across disorders, including ADHD[17?34]. Moreover, we and others have shown that it improves attention and emotion regulation, and alters resting state brain activity and connectivity[35,36]. However, investigations in children and adolescents are far less common[37?40]. To our knowledge, mindfulness as an intervention for ADHD in elementary school children has not been systematically and rigorously studied. We propose to evaluate the feasibility and acceptability of Mindfulness-Based ADHD Treatment for Children (MBAT-C), a novel neuroscience-informed intervention for elementary school children, in an underserved area. MBAT-C is designed for children at precisely the age when ADHD-relevant neurocognitive systems are developing and clinical symptoms begin to appear. There is reason to believe that this innovative treatment will succeed in treating ADHD, given the overlap between neuroscientific mechanisms by which mindfulness exerts its effects and the neurobiology of ADHD[41?44]. Proposed mechanisms of mindfulness include modulation of subsystems of attention, suggesting that a treatment program that targets the attention regulation capacities impaired in elementary school children with ADHD may be efficacious. Forty-five children from Southwest Community Health Center in Bridgeport, CT will be recruited to participate in this randomized- controlled feasibility trial that will compare MBAT-C and medication. Aim 1 is to finalize the MBAT-C manual. Aim 2 is to evaluate the feasibility of MBAT-C on indices of recruitment, randomization, attendance, medication adherence, participation, retention, homework completion, acceptance, and teacher fidelity. Aim 3 is to preliminarily evaluate (within group) pre-, post-, and follow-up measures of ADHD severity, behavior, attention, executive function, working memory, and mindfulness. In accordance with the National Center for Complementary and Integrative Medicine?s framework for developing mind and body interventions, data from this feasibility study will be used in subsequent mechanism- based, multi-site feasibility, and multi-site efficacy studies that will be funded by R61/R33, U01, UG3/UH3+U24 grants, respectively, as well as a K23 training grant. The ultimate goal is to develop a non-pharmacologic intervention for children with ADHD with the efficacy of pharmacotherapy, but without its side effects.